Fórum podpory Firefox

I use Firefox on Linux Debian 11 (Bullseye). After a recent automatic update to Firefox 91.10.0esr, some websites will not load (just sit with a blank page, showing flicking loading symbol). Examples are ocado.com and abelandcole.co.uk. I have tried all the usual things to fix, including, switching off VPN, clearing cookies and caches, running in safe mode, all with no success. Both sites run fine in Vivaldi and Brave. I have eventually got the pages to load by disabling IPv6 in Firefox. Clearly there is a problem with 91.10.0esr. I'm not sure whether the workaround of disabling IPv6 might cause other problems or weaken security or privacy?

Using Firefox 100.0.1. Debian Linux. Dell 1525 with 4G ram.

When playing a certain mp3 file in the browser, if I use the arrow keys, or the mouse, to skip forward or back, there is no response, but the audio stops playing for a period of time, then, finally it starts playing again at the spot it was before.

This does not happen with this file in Chrome, or in VLC. Also, with other mp3s it does not happen in Firefox.

I finally got it to work by converting the file to ogg vorbis, but this is not something I want to make a practice of..

I imported the file back into Audacity, and re-exported it as an mp3. Same result.

Weird... Any ideas?

Thanks,